well, let me explain.
you appear to be of italian origin. so i wanted you to relate to something you feel close to: an italian law. that uses values that seem arbitrary to you. but that are making sense for those that created them. like yahoo, in our case.
since it has correction added to the margin declaration, one would immediately think about the dispute over the box model in ie. assuming you never have heard of it, i hinted you'd search for the subject. meaning: do a little homework
and yes, the underscore and the star used together with a selector usually means ie hacks. that is, making some declarations be understood by a particular UA. and so, i've hinted another homework for you to do.
in your signature you have a last site work. that implies you are a developer, and so i found it hard to believe you've never heard of the underscore hack or the start hack. hence the humorous approach. because i always find it odd, at least, how these 1.4% taxes are imposed on us. i mean, what's wrong with 1%?
both topics have been greatly covered here on SP forums. one quick search should give more answers than you need.
one last thing: if you thought i was trying to make fun of you, i apologise